The study described in this paper is a part of a multi-proxy project, which deals with sediments originating from a former artificial water reservoir situated at the large fortified hilltop site of Vladao. The oldest sediments were deposited around 350 BC and sedimentation continues till recent times. Number of palaeoecological analyses have been applied (pollen, macroremains, charcoal, wood, Cyanobacteria, algae, fungi, Cladocera, chemical elements, radiocarbon dating, archaeological artefact). The present contribution deals with analysis of chitinous fragments of Cladocera found within the trench. The results of this study clearly suggest a connection between the influence of human activity on the hilltop and the trophic status of the water in the cistern. Some phases of increased water eutrophication were distinguished on the basis of Cladocera species preferring nutrient rich water (Chydorus sphaericus, Bosmina longirostris).